A flat panel display has been increasing in size in recent years. For a fixed visual distance, a sense of presence (immersion) improves as the size of the flat panel display increases by an effect of viewing a wide-field image. Note that, in the present specification, a sense of presence refers to a sense produced in a viewer viewing an image as if he or she were present in the world shown in the image.
In addition, at present, practical use of a display with high-resolution, such as 4 K resolution and 8 K resolution, is also about to start. The high-resolution display realizes image expression close to a real object, and therefore improves a sense of reality. Note that, in the present specification, a sense of reality refers to a sense produced in a viewer viewing an image as if an object shown in the image were present before the viewer.
It is considered that an image displayed on a high-resolution and large-sized display often has resolution equal to or lower than resolution of the display. For example, an image displayed on a 4 k resolution display often has 2 k resolution.
In this case, the resolution of the image to be displayed is up-converted to the resolution of the display by using a linear or non-linear scaling technology incorporated in the display, for example. The non-linear scaling technology is described in Patent Documents 1 through 4 and Non-Patent Documents 1 and 2, for example.